Application of Sediment Traps in Global Change Research in Mountain Lakes

Representativity of biota in the biosphere also have similar significance in the lithosphere after their death. Recently, taphonomic representation of biota in the lithosphere has been widely used for minimizing the biases in palaeo-environmental reconstructions including global climate change. In September 2001, a sediment trap was installed at the central area of the Loch Coire Fionnaraich （LCFR）, a small, oligotrophic mountain loch in northwest Scotland for a taphonomic study of cladoceran zooplankton. The trap was emptied on a seasonal basis, where an average 0.14 g dry material was recovered in each season, January, May and August 2002 respectively. A sediment core was also taken from near the sediment trap location. The top 0.5 cm section, the ＇core＇ was used for a comparative study with the trap sediment samples. The planktonic Cladocera consisted of Bosmina coregoni and appeared to have excellent preservation in the trap assemblages. Moreover, some common littoral Cladocera such as Alonella excisa and Aloha guttata appear to be less well preserved in the fossil assemblages. Large littoral taxa such as Eurycercus lamellatus and Aloha quadrangularis were rare in the trap but relatively common and well preserved in the sediment-water interface. It is suggested that taphonomic processes play a dominant role on deposition of fossil remains of Cladocera and caution should be taken while inferring the past environmental changes whilst using fossil assemblages recovered from the lake centre as a representation of the entire cladoceran community in the lake.

The need for data integration to address the challenges of climate change on the Guyana coast

Guyana’s capacity to address the impacts of climate change on its coastal environment requires the ability to mon-itor,quantify and understand coastal change over short-,medium-and long-term.Understanding the drivers of change in coastal and marine environment can be achieved through the accurate measurement and critical anal-yses of morphologies,flows,processes and responses.This manuscript presents a strategy developed to create a central resource,database and web-based platform to integrate data and information on the drivers and the changes within Guyana coastal and marine environment.The strategy involves four complimentary work pack-ages including data collection,development of a platform for data integration,application of the data for coastal change analyses and consultation with stakeholders.The last aims to assess the role of the integrated data sys-tems to support strategic governance and sustainable decision-making.It is hoped that the output of this strategy would support the country’s climate-focused agencies,organisations,decision-makers,and researchers in their tasks and endeavours.

基于WEAP模型的西苕溪流域水质安全保障方案

针对西苕溪流域水质安全问题,基于WEAP建模平台,构建了西苕溪流域水资源评估与规划模型。在模型验证基础上,分析了西苕溪流域2001～2020年河道水功能目标满足度及水供需关系,识别了流域水资源利用存在的问题,并探讨了水源地和中下游区水质安全保障措施及其改善水质的效用,在此基础上提出了西苕溪流域水质安全保障方案。研究表明:TN是影响水源地供水安全的限制性因素,TN、TP是影响河道水功能的重要指标。通过综合实施废水处理厂、节水型设备、退耕还林等水资源管理措施能起到较好地削减TN产出的效果,水源地河道TN浓度降低,基本上能保证全年实现河道Ⅲ类水功能目标,中下游河道TP、TN浓度亦能达到Ⅲ类水功能要求。

Information disclosure and funding successof green crowdfunding campaigns:a studyon GoFundMe

Crowdfunding has become important in increasing financial support for the development of green technologies.Self-disclosed information significantly affects supporters’decisions and is important for the success of green project funding.However,current studies still lack investigations into the impact of information disclosure on green crowdfunding performance.This research aims to fill this knowledge gap by exploring eight information disclosure-relevant factors in green crowdfunding performance.Applying machine learning techniques(e.g.,Natural Language Processing and Computer Vision)and logistic regression,this study investigates 720 green crowdfunding campaigns on GoFundMe and empirically finds that the duration,length of campaign introductions,and length of the title influence fundraising outcomes.However,no evidence supports the impact of goal size,emotion of campaign introduction,or image content on funding success.This study clarifies the information disclosure-related data that green crowdfunding campaigns should consider and provides founders with a constructive guide to smoothly raise money for a green crowdfunding campaign.This study also contributes to data processing methods by providing future studies with an approach for transferring unstructured data to structured data.

Non-Point Pollution from Crop Production: Global, Regional and National Issues

China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though there are still significant uncertainties about the size and importance of emission and leaching rates. A major cause of China’s global role is the overuse of nitrogen fertilizers, which is most serious with intensive vegetable production where application rates can be up to 50% greater than crop needs, but is also a problem with wheat, rice and maize. China’s overuse of nitrogen fertiliser over the past 10-20 years has resulted in non-point source (NPS) pollution from crop production becoming a major cause of water pollution, and the situation is projected to get worse. In contrast, water pollution from point sources such as intensive livestock production and urban or industrial development is being brought more under control. The consequences for air pollution are equally serious. Emissions of nitrous oxide from fertilizers and manures may be so large that China could be responsible for 25-30% of global emissions of this damaging greenhouse gas and of the global warming resulting from it. The main national and local issues relate particularly to low fertilizer use efficiency and the losses of ammonia and NOx that lead to acid precipitation, and leaching and run-off losses that result in high nitrate levels in groundwater and eutrophication of rivers and lakes. The reasons why farmers overuse nitrogen fertilizer are complex and not fully understood. They involve agro-climate differences between provinces and counties, farming systems and farm income structures. Although there is a wide range of institutional and technological improvements that can greatly reduce this overuse rapid progress in reducing NPS is unlikely.

Different radial growth responses to climate warming by two dominant tree species at their upper altitudinal limit on Changbai Mountain

We analyzed the influence of climate change over the past 50 years on the radial growth of two tree species: Korean pine (Pinus koraiensis) and Yezo spruce (Picea jezoensis), located on Changbai Mountain, Northeast China, using a dendrochronology approach to understand factors that limit the altitude for tree species. Elevated temperatures increased the radial growth of Korean pine and decreased that of Yezo spruce. The positive response of tree growth to hydrothermal conditions was the key reason that the upper limit of elevation of Korean pine followed the temperature fluctuation pattern. Increased temperatures and precipitation and longer growing seasons accelerated Korean pine growth. As the temperature increased, correlations between Korean pine ring-width chronology and precipitation changed from negative to positive. In Yezo spruce, increasing monthly temperatures and inadequate precipitation during the middle and late parts of the growing season led to narrow growth rings, whereas decreasing monthly temperatures and sufficient precipitation during the late growing season promoted growth. Rising temperatures and adequate precipitation increases Korean pine growth, possibly elevating the upper range limit in altitude for this species. In contrast, Yezo spruce growth is negatively affected by warming temperatures and limited precipitation. Under future temperature increases and precipitation fluctuations, the upper limit altitude of Korean pine can reasonably be expected to shift upward and Yezo spruce downward.

Regional Moisture Source Changes Inferred from Late Holocene Stable Isotope Records

Qinghai Lake, China, is located near the northern limit of the East Asian summer monsoon （EASM） and thus is an ideal region for studies of past monsoonal changes. However, isotope records from this region reflect the combined effects of multiple climatic factors, and make climatic interpretations difficult. The authors use multi-proxy records, generated from the same sediment core from Qinghai Lake, to disentangle these multiple effects in isotope records and to infer EASM variability during the late Holocene. Records of leaf wax （C2s） δD, lake carbonate 5180 and the Dunde ice core δ18O all indicate a millennial-scale depletion of mean isotopic values at -1500-1250 years before present. Compared with independent lake temperature and salinity records, the authors suggest that this depletion of long-term mean isotopic values must have resulted from changes in moisture sources in this region. In contrast, the authors attribute high-frequency （centennial timescale） C2s δD and ice core δ18O variability dominantly to a temperature effect. The multiproxy records provide a coherent picture in that many aspects of this regional climate （temperature, dryness, and moisture source） are strongly linked to the EASM variability.

Soil temperature estimation at different depths,using remotely-sensed data

Soil temperatures at different depths down the soil profile are important agro-meteorological indicators which are necessary for ecological modeling and precision agricultural activities. In this paper, using time series of soil temperature(ST) measured at different depths(0, 5, 10, 20, and 40 cm) at agro-meteorological stations in northern China as reference data, ST was estimated from land surface temperature(LST) and normalized difference vegetation index(NDVI) derived from AQUA/TERRA MODIS data, and solar declination(Ds) in univariate and multivariate linear regression models. Results showed that when daytime LST is used as predictor, the coefficient of determination(R^2) values decrease from the 0 cm layer to the 40 cm layer. Additionally, with the use of nighttime LST as predictor, the R^2 values were relatively higher at 5, 10 and 15 cm depths than those at 0, 20 and 40 cm depths. It is further observed that the multiple linear regression models for soil temperature estimation outperform the univariate linear regression models based on the root mean squared errors(RMSEs) and R^2. These results have demonstrated the potential of MODIS data in tandem with the Ds parameter for soil temperature estimation at the upper layers of the soil profile where plant roots grow in. To the best of our knowledge, this is the first attempt at the synergistic use of LST, NDVI and Ds for soil temperature estimation at different depths of the upper layers of the soil profile, representing a significant contribution to soil remote sensing.

Sustainability: A view from the wind-eroded field

This article explores the assessment of sustainability in fields subject to wind erosion. In the first part, simple sustainability audits are examined, as of soil depth and nutrients. Direct measurement of these characteristics has many problems, largely because of huge variability in space and time at all scales. Modelling still has its problems, but it may be possible to overcome many of them soon. It is true that wind erosion preferentially removes soil nutrients, but there are imponderables even here. The nutrient balance in many of these soils includes considerable input from dust. In West Africa, it has been shown that the amounts of calcium and potassium that are added in dust are sufficient to fertilize dispersed crops. In mildly acidic sandy soils, such as those found on the widespread palaeo- aeolian deposits, much of the phosphorus is fixed and unavailable to plants by the time it is removed by wind erosion, so that erosion has no added downside. Most of the nutrients carried by dust have been shown to travel close to the ground （even when they are attached to dust-sized particles）, and so are trapped in nearby fallow strips, and are thus not lost to the farming system. Second, the sustalnabillty of a whole semi-arid farming system is explored. Wind erosion in semi-arid areas （like China, the Sahel and Norflawestern Europe） generally takes place on aeolian deposits of the recent geological past. Most of these soils are deep enough to withstand centuries of wind erosion before they are totally lost to production, and some of these soils have greater fertility at greater depth （so that wind erosion may even improve the soil）. Finally some remarks are made about environmental change in relation to sustainability.

A geocomputational analysis of Twitter activity around different world cities

The penetration and use of social media services differs from city to city.This paper is aimed to provide a comparison of the use of Twitter between different cities of the world.We present a temporal analysis of activity on Twitter in 15 cities.Our study consists of two parts:First,we created temporal graphs of the activity in the 15 cities,through which hours of high and low activity could be identified.Second,we created heat map visualizations of the Twitter activities during the period of 19 September 2012–25 September 2013.The heat map visualizations make the periods of intense and sparse activity apparent and provide a snapshot of the activity during the whole year.

Does the Negative Arctic Oscillation Always Favor Winter PM_(2.5) Diffusion in North China?

Previous studies have reported a close relationship between the negative Arctic Oscillation(AO)and the PM_(2.5)(particulate matter with a diameter of 2.5μm or less)diffusion in North China in winter.Using the North China regional mean meridional wind at 850 hPa derived from the ERA5(ECMWF Reanalysis version 5)reanalysis data in 1979–2022 as a useful substitute for station observed PM_(2.5) concentration(since the latter is available only since 2014),our study detected strong/weak northerly events representing the abnormal PM_(2.5) diffusion/accumulation events,and revisited the AO–PM_(2.5) diffusion relationship in North China during 1979–2022.The results show that only when the AO was characterized by a 2-month continuously negative/positive phases and with twin peaks respectively before and after the diffusion/accumulation events,would there be higher occurrences of the abnormal PM_(2.5) diffusion/accumulation.The second peak of negative AO acted to prolong the strong northerly winds by an average of 2 days.Further analysis reveals that the AO with twin peaks always has a footprint in the stratospheric northern annular mode(NAM)during the abnormal PM_(2.5) events,and the coupling between the stratosphere and troposphere plays a critical role in the second peak of AO.Vertical propagation of baroclinically amplifying waves leads to changes in isentropic meridional mass fluxes in the stratosphere following the changes in the troposphere.The stronger/weaker poleward mass fluxes increase/decrease the polar mass in the stratosphere,which dominates the total column air mass changes and leads to the second peak of AO.Considering the subseasonal predictability of the stratospheric NAM based on existing evidence,particular attention should be paid to these AO-related abnormal PM_(2.5) diffusion and accumulation events in North China because they might be more predictable at a longer lead time.

青海湖沉积岩芯记录的青藏高原东北部过去800年以来的降水变化

对取自中国最大的内陆封闭湖泊青海湖深水区长约80 cm的短钻岩芯,用210Pb,137Cs和岩芯对比建立年代序列,用5年分辨率的自生碳酸盐同位素、粒度、碳酸盐和有机质含量来重建青藏高原东北部过去800年来的气候变化历史.发现青海湖湖盆的不同深水区岩芯具有很好的对比性,湖盆西部沉积速率最大,东部最小.在湖盆南部短钻岩芯Qing-6所在位置,近期平均沉积速率为0.1004 cm/a.氧同位素和粒度资料揭示的过去800年的有效降水变化与古里雅和敦德冰芯记录的冰川积累量一致.公元1200-1500年的300年中总体为干旱气候,公元1500-1560年相对湿润.1560-1650年和1780-1850年的两个干期是西南季风减弱的结果.1650年以来的有效降水总体增加是亚洲西南季风增强所致,一直持续到1950年前后.高原上的小冰期除早期以外,以水汽增加为特征.沉积物有机质含量变化有200年左右的周期,与1850年以前大气△14C变化同步,表明湖泊生物生产力响应了太阳活动变化.

新疆博斯腾湖记录的亚洲内陆干旱区小冰期湿润气候研究

利用中国内陆干旱区最大淡水湖泊博斯腾湖中心的钻孔岩芯,在137Cs,210Pb和AMS14C测年基础上,对湖泊岩芯孢粉组合、碳酸盐含量和粒度等多指标进行了分析.结果发现,近1000年来,内陆干旱区气候变化经历了3个主要阶段,1000～1500AD干旱、1500～1900AD湿润和1900AD以来的再次变干,近千年来在几百年尺度上的气候变化组合以暖干和冷湿为主.在公元1500～1900年的小冰期期间,多种代用指标均出现显著变化,孢粉蒿藜比显著增大,碳酸盐含量明显降低,而粒度明显偏粗,说明博斯腾湖流域降水增加,气候比今湿润,这与近百年来全球变暖条件下内陆干旱区出现的暖干气候形成显著对照.亚洲内陆冰芯、湖泊、河流、树轮、沙漠等记录均记录了西风环流显著影响区较为湿润的小冰期气候,出现明显的冷湿气候组合,博斯腾湖岩芯记录的湿润小冰期气候具有代表性.西风环流影响区湿润小冰期气候可能是全球性普遍降温导致有效湿度增加和因北大西洋涛动负异常而导致的西风影响区降水增加两个因素共同作用的结果.

Humid Little Ice Age in arid central Asia documented by Bosten Lake, Xinjiang, China

Short sediment cores retrieved from Bosten Lake, the largest inland freshwater lake in China, were used to explore humidity and precipitation variations in arid central Asia during the past millennium. The chronology of the cores was established using 137Cs, 210Pb and AMS 14C dating re- sults. Multi-proxy high-resolution analysis, including pollen ratios of Artemisia and Chenopodiaceae (A/C), carbonate content and grain size, indicates that the climate during the past millennium can be divided into three stages: a dry climate between 1000―1500 AD, a humid climate during the Little Ice Age (LIA) (c. 1500―1900 AD), and a warm dry period after 1900 AD. On centennial timescales, the climate change in northwestern China during the past 1000 years is characterized by oscillations between warm-dry and cold-humid climate conditions. All the proxies changed significantly and indi- cate increased precipitation during the LIA, including increased pollen A/C ratios and pollen concen- trations, decreased carbonate content and increased grain size. The humid period during the LIA re- corded by the Bosten Lake sediments is representative of arid central Asia and is supported by nu- merous records from other sites. During the LIA, the water runoff into the Keriya River and Tarim River in the Tarim Basin increased, while the ice accumulation in the Guliya ice core increased. Additionally, the lake levels of the Aral and Caspian Sea also rose, while tree-ring analysis indicates that precipita- tion increased. We hypothesize that both the lower temperature within China and the negative anomalies of North Atlantic Oscillation (NAO) during this period may have contributed to the humid climate within this area during LIA.

A high-precision heuristic model to detect home and work locations from smart card data

Smart card-automated fare collection systems now routinely record large volumes of data comprising the origins and destinations of travelers.Processing and analyzing these data open new opportunities in urban modeling and travel behavior research.This study seeks to develop an accurate framework for the study of urban mobility from smart card data by developing a heuristic primary location model to identify the home and work locations.The model uses journey counts as an indicator of usage regularity,visit-frequency to identify activity locations for regular commuters,and stay-time for the classification of work and home locations and activities.London is taken as a case study,and the model results were validated against survey data from the London Travel Demand Survey and volunteer survey.Results demonstrate that the proposed model is able to detect meaningful home and work places with high precision.This study offers a new and cost-effective approach to travel behavior and demand research.

Street networks in relation to landforms： Implications for fast-growing cities

In addition to socio-economic factors, major landforms may affect the city structure and urban form. Here we show that landforms have significant effects on the city shape and street patterns of the fast-growing Iranian cities of Dezful （a river） and Khorramabad （moun- tains and valleys）, but no clear effects on the cities of Yazd and Nain. Also, where the street orientation is peaked, the Gibbs/Shannon entropy （a measure of dispersion or spread） is low, but increases as the distribution becomes more uniform because of landform constraints. The streets in the old inner parts of all the cities are, on average, shorter and denser （more streets per unit area） than the streets of the newer outer parts. The entropies of the outer parts are also greater than those of the inner parts, implying that the street-length distribution gradually becomes more dispersed or spread as the city expands. All these cities have been fast growing in the past decades, with the newer outer parts expanding rapidly. As shown here, the rapidly formed outer parts （with greater dispersion in street patterns） have significantly different textures from those of the older inner parts, indicating different functionality and growth processes. These quantitative methods for street-network analysis can be used worldwide, particularly for analysing the effects of landforms on city shape and texture.

The nitrogen cycle,scientific uncertainty and policy relevant science

Much of the research on the nitrogen cycle aims to improving scientific understanding but is not focused specifically on removing or reducing the scientific uncertainties that constrain policy makers in the formulation of appropriate responses to old or emerging environmental problems. Policy makers, for example, commonly find it difficult to assess the spatial or temporal importance of the various risks to human and ecosystem health that stem from man's interference with the natural N cycle. This paper will justify this conclusion by reference to the findings of a recent study on non-point pollution from crop production in China. The findings concern the perceived risks of groundwater nitrate to human health; uncertainties about critical NOx levels and their interactions with other pollutants; various other dimensions of man's impact on the N cycle. The paper will go on to suggest a more systematic process or pathway by which scientists can select and design their research in a manner that could give more effective support to policy makers.